Cardinals RB Ryan Williams has yet to make it through an NFL season. / Scott Rovak, US Presswire

by Scott Bordow, USA TODAY Sports

by Scott Bordow, USA TODAY Sports

The Arizona Cardinals have lost running back Ryan Williams for the rest of the season with a left shoulder injury.

Williams, who injured the shoulder in Arizona's 17-3 loss to the St. Louis Rams on Thursday, will require season-ending surgery, coach Ken Whisenhunt said Monday.

It's the second straight year Williams has been hurt. He missed all off his rookie year after tearing his patellar tendon in the preseason.

"I feel horrible for Ryan," Whisenhunt said.

Initially, the Cardinals didn't think Williams, who leads the team with 164 yards rushing, was seriously hurt on the hit by Rams' safety Darian Stewart. But subsequent tests revealed that Williams would require surgery. Whisenhunt declined to talk about the precise details of the injury.

"The timetable for recovery is three months. That puts him at the end of the season," Whisenhunt said.

Williams' injury further depletes an already-thin position. Beanie Wells (turf toe) will be out at least five more games, leaving the Cardinals with LaRod Stephens-Howling, who has missed the past two games with a hip injury, William Powell and Alfonso Smith. Combined, the three players have 15 carries for 10 yards this season.

Whisenhunt said he feels "good about the guys we've got," but added the Cardinals might look for reinforcements at tailback.

"If there's an opportunity there we'll try to act on it," Whisenhunt said.

Wells and Williams were supposed to give the Cardinals a formidable one-two punch out of the backfield this season, but those plans have been dashed.

"That's the NFL. Teams have to fight through adversity," Whisenhunt said. "We've done a good job of that the first five week of the season. Now we have another challenge."